ABB S800 Product Manual page 79

Section 2 Product Description
TB840/TB840A ModuleBus Modem and TU807/TU840/TU841/TU848/TU849
Module Termination Unit
The TB840/TB840A ModuleBus Modem is a fiber optic interface to the Optical
ModuleBus. TB840/TB840A is used in redundancy configurations where each
module is connected to different Optical ModuleBus lines, but connected to the
same electrical ModuleBus.
Termination Unit TU840 connects TB840 to redundant I/O. Termination Unit
TU841 connects TB840 to non-redundant I/O.
Termination unit TU848 has individual power supply connections and connects
TB840 to redundant I/O. Termination unit TU849 has individual power supply
connections and connects TB840 to non-redundant I/O. TB840 can be used as
single with TU807.
The ModuleBus Modem has an electrical and an Optical ModuleBus interface
which are logically the same bus. A maximum of 12 I/O modules can be connected
to the electrical ModuleBus and up to seven clusters can be connected to the fiber
optic ModuleBus.
The cluster address sets by a rotary switch on the Termination Unit
TU807/TU840/TU841/TU848/TU849 in range 1 to 7.
The TB840/TB840A ModuleBus Modem provides 24 V d.c. protected (from the
source) and an isolated, protected 5 V dc power to the cluster's I/O modules by way
of the electrical ModuleBus connection. One power source (single or redundant 24
V d.c.) can be connected to the power terminals (L+ & L-). The redundant power
supply can be supervised via inputs SA and SB.
The rotary switch and the connectors for power supply is located on
TU807/TU840/TU841/TU848/TU849. See
Figure
3BSE015969-600 A
29.
Figure 31, for dimensions see also
ModuleBus
79